After 3 months, activated NKG2A+ and NKG2C+ cells were still significantly higher in all COVID-19 patients compared to HD, although the differences between NKG2A+ CD69+ and NKG2C+ CD69+ subsets were no longer significant in the mild cohort at T3M, as well as in the other disease groups (data not shown). Here, KLRC2 is linked to COVID-19.